Recording or indicating instrument



May 6, 1941. c, YQUNG 2,241,233

RECORDING OR INDICATINQ INSTRUMENT Original Filed Apri1 21, 1938. 2 Sheets-Sheet 1 INVENTOR Claude D. Youny av g m M 0m ATTORNE s May 6, 1941. c; D. YOUNG RECORDING OR INDICATING' INSTRUMENT v Original Filed April 21, 1938 2 Sheets-Sheet 2 INVENTOR Claude D. Youn ATTORNE s Patented May 6, 1941 RECORDING on. mmca'rmo INSTRUMENT Claude D. Young, Foxboro, Mass, assignor to The Foxboro Company, Foxboro, Masa, a corporation of Massachusetts Original application April 21, 1938, Serial No. 203,302. Divided and this application January S PATENT OFFICE.

25, 1939, Serial No. 252,753 I 6 Claims. (Cl. 73-151) The invention herein described pertains to improvements in instruments for indicating, recording and/or controlling variable conditions; this application being a divisional of my co-pending application Serial No. 203,302, filed April 21,

In the embodiments chosen to illustrate said invention several pressure responsive elements are provided in a single instrument casing for recording on a single chart the values being ments.

of temperature.

responsive unit.

which may be mounted in the same casing.

part pointed out hereinafter.

eral embodiments of the invention:

ment case connected for surface mounting;

bled with the instrument case;

the instrument case;

and

Referring to the drawings wherein like reference characters designate like parts throughout the several views, there is illustrated in Figure 1 a recording thermometer of the four-pen type, in which pens Ilia, lb, We and id are suitably mounted for movement about a common axis IQ! of rotation by a mounting assembly as described in United States Patent to E. H. Bristol et al., No. 1,778,702, dated October 14, 1930. The pen arm levers Ila, lib, He and lid,

of known construction, move the pen arms and measured by several temperature responsive eleare connected by links I211, l2b, I20 and lid with The temperature responsive elements the levers of the measurlng'element assemblies commonly used for this purpose each comprises generally designatedA, B, C and D. a thermometer bulb filled with mercury or other The helical pressure springs of the element asfluid which varies in a characteristic with change semblies are suitably connected with the capil- The thermometer bulb is 10- laries Ha, [3b, like and B11 which extend through cated at a place whose temperature is to be openings in the cylindrical side wall of an inmeasured and is connected by.a small bore or strument casing generally designated IS, the, capillary tubing with a spiral tube or other flexprotective tubing Ha, lib, lie and Md for the ible element one end of which is free to move capillaries being secured to the case wall, by in response to pressure variations in the tubing means to be described. The tubing is in turn caused by changes of temperature in the bulb. connected with a responsive element or meas- .This latter element is mounted in the casing and Y uring bulb such as shown at 8 so that variations its free end is connected through suitable linkin the responsive element are transmitted to the age mechanism with a pen moving over the chart measuring element. The measuring element, the on which the record is recorded. Usually the capillary tubing and protective tubing and the bulb, tubing and element are filled and sealed responsive element together form a unit which with whatever fluid is used and calibrated as a hereinafter will be referred to as the responsive unit.

It is an object of the present invention to pro- While a four-pen recorder is illustrated in Figvide an improved casing or housing into which ure 1 it will be understood that such is by way the responsive units or any of them may be in- I of example only and that the number of pens serted and from which they may be removed in and associated measuring units may be decreased part or as a unit without disturbing other'units or increased asv desired. V 1

It is desirable that the construction of the Other objects will be in part obvious and in casing permit the assembly of the measuring e1ement,capillary tubing, protective tubing and In the drawings wherein are illustrated sevresponsive element in a substantially permanent relationship independently of the instru- Figure 1 is a perspective view of amultiple 40 ment casing and the mounting of these parts in pen recorder housed in a standardized instruthe instrumentcasing after such assembly. One

. of the advantages of such a construction is that Figure 2 is a part perspective view illustrating if one of the responsive units becomes damaged the manner in which a measuring unit or .reor needs to be changed f any other reason sponsive unit may be removed from or assemwhile in service. the particular unit y be moved from the instrument casing without dis- Figure 3 is a detail illustratingthe preferred turbing the other responsive units and be remode of connecting the measuring unit with placed or repaired as desired, all without the l need of returning the instrument casing to the Figure 4 is a perspective view similar to Figfactory. So, too, with such an arrangement the ure 1, but illustrating an assembly in which the instrument or part of the instrument may be instrument case is adapted for flush mounting; converted from one type of service into another a type in the field without the necessity of re- Figure 5 is a section along line 5-5 of Figure 4. turning the entire instrument to the factory.

' Referring to Figures 1, 2 and 3, there is illustrated one embodiment of the invention whereby an instrument casing or case is provided in which the responsive units may be assembled or from which they may be removed without disturbing the connections between the measuring element, the capillary and protective tubing and the responsive element. In Figures 1 and 2 the responsive units are shown inserted in the instrument casing in such manner that the casing may be wall mounted. The peripheral or cylindrical side wall of the casing is provided with a plurality of circular openings such as the small area opening 80 into which opens one end of a. slot 8|, the other end opening into the top opening of the case. A protective tubing M which protects the capillary l3 exteriorly of the casing is secured to a connector or anchoring member 82 having a threaded portion 83 of such diameterthat it may pass through the opening 88, the body portion of the connector 82 being of greater diameter to provide a shoulder which may bear against the outer surface of the case wall. The connector assembly includes a nut 84 adapted to be threaded on to the threaded extension 83 of the connector from the inner wall of the case, thus to secure the connector to the case.

Assuming that it is desired to assemble a measuring unit with an instrument casing as described, nut 84 is unthreaded from the connector 82 and slid along the capillary l3 so that it is positioned relatively within the casing. With the measuring unit held generally as shown in Figure 2, the capillary is inserted through the slot 8| until the connector 82 registers with hole 80 and upon projection of the threaded portion 83 into the hole, nut 84 is threaded on the connector to secure the capillary I3 and protective tubing l4 to the side wall of the instrument case. The measuring element assembly is inserted into the casing through the open top thereof, and is secured in its proper position against the back of the casing.

To disassemble a measuring/unit from the case, the reverse of the assembling operations are practiced, it being understood that a unit or portions thereof may be removed from the casing without disturbing the operation of other units operatively assembled therewith, and without requiring that the capillary be disconnected from the measuring element assembly as was heretofore necessary according to known practices.

After assembly of the measuring unit with the case as described, slot 8| is adapted to be closed by a key 85 which may be slightly tapered in section whereby it is frictionally held within the slot yet is capable of being knocked out when it is desired to disassemble a measuring unit from the case.

While four connections are illustrated by way of example in Figure 1, it will be understood that in certain instruments a lesser number of pens will be required. In this instance, connections are made as described between the casing and the measuring units in required number for a particular installation, and the unused connecting holes 89 and slots 8| are plugged, the holes 80 being plugged by a disc which can be knocked out when desired, and the slots 8| being plugged by keys 85 as described. If it is desired to add a pen or pens to the instrument as, for example, when the instrument is converted from one type of service to another, the disc and key plugs are knocked out and the added measuring units are assembled with the manner described.

The back of the casing as illustrated in Figure 1 is so constructed that the capillary tubing may enter through the back rather than through the side wall, as is necessary when the casing is flush mounted and as shown in Figure 4, thus to standardize the casing for both surface and flush type of mounting. Referring to Figures 1 and 4, the back of the casing is provided with a circular hand hole 98 of substantia1 area adapted to be closed by a hand hole cover 9|. By reference to Figure 5 the cover has a marginal flange 92 seating in an outer circular recess surrounding the hand hole 99, whereby the cover is prevented from moving. into the casing. To .removably secure the cover to the back of the casing, washer headed securing screws 93 are provided on the cover, the heads of which extend over the peripheral edges of the cover and hand hole 98. Hence, unintentional removal of the cover following its mounting in covering relation with reference to the hand hole is prevented.

Disposed in spaced relation around the hand hole opening is a plurality of circular openings 95 illustrated by way of example as four in number. These holes 95 communicate with hand hole 99 through connecting slots 96. When the instrument is to be surface mounted, with connections made through the side wall of the casing as illustrated in Figure 1, the connector holes 95 and slots 96 are or may be plugged by means of discplugs 91 and slot keys 98. However, when the instrument casing is to be flush mounted, as illustrated in Figure 4; connector holes and the related slots 8| are plugged, plugs 97 and casing in the keys 98 knocked out, and connections between the measuring units and the casing are thereupon made through the back of the casing as illustrated in Figure 4.

In assembling measuring units with a casing .to be flush mounted, the clock motor (not shown) if mounted in the casing is removed through the front cover opening. Thereupon the measuring element assembly is inserted into the casing through the hand hole opening for securement to the casing back as described in connection with the Figure 1 construction and the capillary moved through slot 96 until its connector may be positioned in a hole and secured by a nut I80. To disassemble from or replace a measuring unit in the field, it is necessary to remove the clock motor to provide access to the cover plate 9| which is normally located in covering relation with reference to the hand hole 90. The cover is then removed, with the hand hole thereupon providing suflicient opening for passage of the measuring element therethrough.

As shown in Figure 4, securing nuts Hill which correspond in function to the securing nuts 84,

,shown in Figures 2 and 3, may secure against the back face of the instrument number plates I |8| on which may be inscribed data identifying the particular measuring unit. While not illustrated in Figure 1, nuts 84 may similarly secure against the inner face of. the casing side wall identifying tags similar to tags NH. The provision of identifying tags associated with each unit provides an extremely simple means by which the manufacturer upon order can supply a new measuring unit of the same characteristics as those of a damaged unit, so that replacement can be effected in the field.

As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained inthe above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. In an instrument of the character described, in combination, an instrument casing having a side wall whose forward edge defines a front opening, and a back wall,'the side wall having therein a small area opening and a slot extending from said opening to the'forward edge of the wall, the back wall having a hand openingof relatively large area, a hole of small area, and a slot extending between said hand opening and hole, a responsive unit including a measuring element and a tubing connected thereto, the arrangement being such that the measuring element is selectively insertable through and removable from the casing through the frontopening, with the tubing movable therewith through the side wall slot to and from a position in the side wall hole, or is insertable through and removable from the casing through the hand opening in the back wall, with the tubing movable therewith to and from a position in the back wall hole of small area, and means for closing the unselected small area hole and its related slot.

surface or flush mounting, the casing having a side wall and a back wall, the front edge of the side wall defining a front opening, and the side wall having therein a small area opening and a slot extending between the front and small area openings, the back wall having therein a large area opening,.a small area opening, and a slot extending between said openings.

4. An instrument casing assembly including a wall having edge portions defining a large area opening, said wall also having a small area opening and a slot extending between and connecting said openings, an anchoring device removably se- 1 cured in said small area opening and including a 2. In a recording instrument, in combination,

a responsive unit comprising a measuring element, a responsive element, a capillary tubing connecting said measuring and responsive elements and a protective tubing over said capillary tubing, all inseparably connected; an instrument casing having a side wall whose front edge defines a front opening, and a back wall, the side walls having therein a plurality of small area openings and slots extending from said openings to the front edge of the wall, the back wall having a hand opening of relatively large area and a plurality of holes of small area and slots extending between saidholes and said hand opening; said measuring element being selectively insertable through and removable from the casing through means for sealing the unselected small area holes and related slots, and means for normally closing the back wall hand opening.

3. An instrument casing adapted for either nipple held against lateral displacement from said small area openingby inner edge portions thereof, and a tube extending from said nipple for connection with an instrument in said casing and adapted to pass through said slot when said nipple is inserted and removed from the small said element may be inserted and removed from the casing, a smaller area opening, and a slot connecting said two openings to provide a passage through which the capillary tube is moved with the measuring element as the latter is inserted into or removed from the casing, and an anchoring device at one end of said protector tube having a portion of. greater diameter than the width of saidslot and releasably engaging with said smaller opening to secure said protector tube to the casing and to permit its ready attachment and removal along with insertion and re,- moval of the measuring element and the capillary tube.

6. An instrument casing having a wall with edge portions defining a large area opening and having a small area opening and a slot narrower than said small area opening to provide a relatively constricted passageway connecting said large and said small area openings, a connector nipple removably secured in said small area opening, a removable key slidably engaging said slot and with an inner end bearing against said nipple when the latter is positioned in said small area opening, and a cover cooperating when closed with the said edge portions, of the large area opening and overlying an outer end portion of said slot and said removable key therein.

CLAUDE n. YSU G. 

